diff --git a/ChangeLog b/ChangeLog
index ee043d61ca..1a9681143d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,7 +1,7 @@
-Thu Feb 21 14:47:09 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Thu Feb 21 14:49:40 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
-	* io.c (argf_set_encoding): uses current_file after check for next
-	  input.
+	* io.c (argf_set_encoding): uses current_file after check if next
+	  input is available.
 
 Thu Feb 21 11:10:49 2008  NARUSE, Yui  <naruse@ruby-lang.org>
 
diff --git a/io.c b/io.c
index c17fc9e93f..61cfa97b83 100644
--- a/io.c
+++ b/io.c
@@ -6103,7 +6103,7 @@ argf_set_encoding(int argc, VALUE *argv, VALUE io)
 {
     rb_io_t *fptr;
 
-    if (next_argv()) {
+    if (!next_argv()) {
 	rb_raise(rb_eArgError, "no stream to set encoding");
     }
     rb_io_set_encoding(argc, argv, current_file);